In joining pipe sections so that fluids contained in the pipe will be sealed therein, various sealing joints have been utilized. The most common sealing joint comprises an "O" ring which is secured over the male projecting end of a pipe which is subsequently inserted into a corresponding female end of an adjoining pipe or coupler. In a similar structure, a separate male coupler has "O" rings inserted over each of its ends and is inserted between two female ends of adjoining pipes.
One problem encountered at pipe joints is the leakage of water or fluid either outwardly from the inside of the pipe to the outside thereof or inwardly from the outside of the pipe to the inside thereof. In water lines, the water inside the pipe is usually under pressure and there is a tendency for such water to leak through the joints to the exterior of the pipe. In sewer and drain lines, there is a tendency for ground water to build up around the pipe and leak inwardly into the sewer system. This type of leakage is undesirable in that it floods the sewer with drain water and hampers the sewer in performing its intended function.
Sealing members have been devised which respond to increases in internal or external pressure to effect a tighter seal. One type of seal comprises basically an "O" ring which includes an inner, annular slot therein so that fluid in a water pipe tends to flow into the interior of the seal and expand it outwardly. Another type of seal includes protruding flanges which are forced outwardly against the surfaces they abut in response to increases in internal or external pressure. Unfortunately, such flanges tend to get hung-up on one pipe joint member as it is being slid onto another pipe joint member, thereby causing the entire seal to be moved out of its proper place. This fouls the sealability of the entire joint.
To help prevent seals from dragging on a pipe joint member as it is slipped over another pipe joint member, workmen typically lubricate the seal with some type of grease. While this is helpful, it is a messy and time-consuming operation which unduly adds to the cost of constructing a pipe line.